Discussing the furor with ET Online, Kick-Ass 2 actress Mortez suggested that Bieber likely meant no offense with his guest book message about Frank.

"I very much respect Anne Frank and what she went through. [It] is a very serious situation and you know to make a joke of it sometimes is kind of inappropriate," she explained.

"But at the same time you can kind of think of the angle, well you know, 'You've got to bring light into those dark situations'."

Moretz added: "I don't know, a lot of people are Beliebers... maybe she would have been a Belieber."

Photo gallery - Bieber's bad boy antics:

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Justin Bieber performs at lingerie label Victoria's Secret's fashion show in New York last year. The 19-year-old reportedly invited supermodel Cara Delevingne (pictured) to an after party despite still dating Disney star Selena Gomez.
Copyright: Rex Features
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